Pneumatic-despatch-txjbe apparatus



E. B. PERRINE.

PNEUMATIC DESPATCH TUBE APPARATUS.

APPLICATION FILED MAR. 4. IQIB.

Patented June 3, 1919.

' UNITED STATES PATENT ()FFI-OE.

EMMETT B. PERRINE, 0F MINNEAPOLIS, MINNESOTA.

P1\ T EUMATIC-DESPATCH-TUBE APPARATUS.

Application filed March 4, 1918. Serial No. 220,116.

My invention relates to a pneumatic def spatch tube apparatus in which carriers such as cash carriers are conveyed y from point to point by pressure of air. The object' of my invention is to provide for regulating the velocity and volume of air flowing through the various transmission tubes of a multiple line system by means of mechanism operated by the velocity of trai'el of the air. Since energy is consumed in forclng the carriers through the system, it 1s evident that when no carriers are belng conveyed there will be a tendency for a' large volume of air traveling at a high velocity to be circulated through the system, and that as the number of carriers in transit is increased there will be a tendency for the velocity and volume of the air to decrease. The object of my invention in particular is to maintain a constant velocity and volume of air through the transmission tubes regardless of the number of carriers in transit.

The full objectsand advantages of my in vention will appear in connection with the detailed description thereof and are particularly pointedout in the claims.

Referring to the drawing, the single figure, designated as Figurel, is a diagrammatic view mostly in vertical section.

An air pump 2 of usual construction has its pressure side connected with a main pressure pipe 4 and its suction side connected with a main 'suctiom pipe 6. From the main pipe 4 there are led a plurality of transmission tubes 8, two only of which are shown. Each of the tubes 8, near the point where it is connected with the main pipe, is provided with a regulating chamber 10 in which is a damper or butterfly "alve 12 mounted on a short rock-shaft 14, one end of which is extended a short distance through the wallof the chamber and to which end is'se'cured an arm 16. A link 18 connects this arm to one arm of a bell-crank lever 20 pivoted at 22 to a bracket 24, which for convenience may be secured to the transmission tube. The armof thebell-crank to which the link 18 is connected passes Specification of Letters Patent.

Patented June 3, 1919.

- through a slot in the wall of the chamber and has a curved slot 26 secured thereto, to cooperate with a curved portion on the wall of the chamber, the curvature of these parts having the pivotal point 22 as a center. From this it is evident that the slide 26 constitutes a closure for the slot regardless of the position of the bell-crank lever. On the end of this lever, inside the chamber, is'an impact cup 28. The other end of the bell-crank has an extension 30 provided with an adjustable weight 32 to permit regu- 'lation of the constant velocity of the air current as desired. The operation of this portion of the apparatus is obvious. When there are no carriers in the transmission tube, the impact of air on the. cup, 28 Will lift the same, and by means of the connection through the link 18 and the arm 16 will tend to close the damper 12. When there is a carrier in the tube, which may be inserted through the hinged door at the carrier inlet 34, the tendency is to reduce the velocity of the air current and the cup 28 will drop, thereby opening the damper 12 to permit the air to pass more freely, and thus maintaining a constant velocity and volume.

Leading into the main suction pipe 6 are a plurality of transmission tubes, two only of which are shown at 36 and 38 and which are provided with regulating devices similar to that already described. The arrangement and position of the tube 36 is such that it is convenient to place the regulating de-' vice at the intake end 40 in a regulating chamber 42. The regulating device associated with this chamber is in general the same as that previously described, and the corresponding parts are numbered the same. At this position, however, -I find it desirable to add a dash-pot in order to prevent too rapid movement of the damper 12. I do this by extending" the arm 16 and to the end thereof pivot ng a piston rod 44 having a piston 46 operating in a cylinder 48.

The arrangement of the other suction tube 38 is such that it is preferable to locate the regulating device near the point where the transmission tube leads into the main suction pipe 6. The regulating chamber is designated by the character 50, and associated with this chamber is a regulating device which is the same as that in the chamber 10 in reversed position excepting that in, this position the bell-crank lever must still have its weighted arm extending downwardly. This arm is therefore extended in the opposite direction relatively to the cup 28, and I have accordingly designated this bell-crank by the character 52- 54 or 58, the tend'encv is t reduce the velocity and volume of airpassing through the tube 36, and the damper 12 near the inlet end of this tube Will be opened to maintain a constant velocity of air. When "an operator inserts a carrier in the inlet end 56 or the carrier inlet 60 of the transmission tube 38, the damper 12 near the main suction pipe 6 will be opened to maintain a constant velocity of air. The advantages and operation of my device Will be obvious from the foregoing description. -A constant velocity of air is maintained -in the transmission tubes regardless of how many carriers are in transit or whether there are any. The operation of the whole system is thus rendered more satisfactory and the force with which successive carriers"strike the desk or other lace provided to receive them is the same. There will be less consumption of power since an excess rush of air through the tubes "is prevented when carriers are not being sent. If desired, the apparatus disclosed herein may be used in connection with the cut off valves shownin my prior Patents, 1,180,603 and 1,180,604 or similar cut off valves.

- I claim:

.1. A pneumatic despatch tube apparatus comprising transmission tubes, means for causing currents of air to pass through said tubes, and impact means for maintaining a constant velocity of travel of said air currents.

2. A pneumatic despatch tube apparatus comprising transmission tubes, means for causing currents of air to pass through said tubes, and impact means controlled by the velocity of said air currents for maintaining the same constant. v

3. A pneumatic despatch tube apparatus comprising transmission tubes, means for causing currents of air to pass through said tubes, regulating chambers in said tubes, and impact means associated with each of said chambers for maintaining a constant velocity of travel of said air currents.

' 4. A pneumatic despatch :ibe apparatus eos ice I for controlling the position thereof according to the velocity of the air current passing through said chamber.

5. A pneumatic despatch comprising transmission tubes, means for causing currents of air to pass through said tubes, regulating chambers in said tubes, a damper in each of said chambers, an impact cup in each of said chambers, and connections between said cup and said damper whereby the position of the damper is'regucomprising transmission tubes, means for tube apparatus lated according to the velocity of the air current passingthrough said chamber.

6. A pneumatic despatch tube apparatus comprising transmission tubes, means for causing currents of air to pass through said tubes, regulating chambers in said tubes, a

damper in each of said chambers, an impact .cup in each of said chambers,connections between said cup and said damper to cause them to operate in unison, and means for varying the degree of impact required to move said cup.

7. A pneumatic despatch tube apparatus comprising transmission tubes, means for causing currents of air to pass through said tubes, regulating chambers in said tubes, a damper in each of said chambers, an impact cup in each of said chambers, a lever to which saidcup is secured, said lever passing through a slot in the wallet said chamber,

'means for keeping said slot closed regardless of the position of said lever, and connections between said lever and said chamber.

. 8. A pneumatic despatch tube apparatus comprising transmission tubes, means for causing currents of air'to pass through said tubes, regulating chambers in said tubes, a damper in each of said chambers, a rock shaft to which said damper is secured, an

end of said rock-shaft passing through the wall of said chamber, an arm secured to said rock-shaft, a link pivotally connected to said arm, a lever pivotally connected to a support outside the wall of said chamber, one arm of which passes through said wall. an impact cup in said chamber secured to the inner end of said lever arm, the latter being pivotally connected to said link outside said chamber, and an adjustable counterweight on the other arm of said lever.

In testimonywhereof I hereunto ailix my 1 signature.

EMMETT B. P'ERRIN'E. 

